I had a root canal done 8 months ago on tooth 2 it has recently become loose with no pain. dentist says xrays look good, so why is it loose?

Can't guess: Your tooth should not feel loose, if it is and your current dentist can't tell, you may want to get a second opinion. We can not guess over the internet, unless we can see it and test it we can not advise you. Good luck and hope it feels better.

Unknown: Radiographs are not the only criteria for determining the cause of a loose tooth. Periodontal probing and checking the occlusion are two other contributing factors. Please see a periodontist.